pope benedict is a shy leader. but he's unpredictable, unprecedented. and it might just guarantee his legacy. at 85, he is silver-haired and cerebral and says he simply can't keep up. pope benedict xvi tells his cardinals in latin, quote, i had to recognize my incapacity to adequately fulfill the ministry entrusted to me. in the last year, benedict grew increasingly frail. >> he certainly slowed down a bit. you could tell he had trouble negotiating steps. he started using the cane several months ago. >> reporter: but the german pope never slowed down, putting the church on an orthodox path. he opposed homosexuality and female priests. he tried to heal wounds, apologizing to victims of sexual abuse. >> they have to come to terms with the priest scandal. they have to be more candid and honest about it. >> reporter: benedict filled stadiums. but he was always a bookworm, more comfortable writing. many are calling for a more dynamic pope. and thanks to the first papal retirement in six centuries, cardinals might be willing to choose a young ur successor. >>